There has been an intention in the industry of mass transit vehicles to provide a vehicle body which is formed primarily of a composite material. Such composite materials generally comprise fibreglass reinforced resin sheets and often these are formed with a foam or other core layer between the sheets. The primary intention is that the structure be formed substantially wholly from such composite materials. The intention is that such materials will reduce weight and provide a superior corrosion resistance. One technique is to provide molds in which the body is shaped and formed from separate pieces which can then be connected together. However one highly desirable feature is that the structure can provide multiple different vehicle lengths to satisfy customer demands.
A number of attempts have been made for example, by Grumman ATTB, NABI who provided 40 and 45 feet length “Compobus”, a proposal by ABI, a proposal by TPI under the trade name “Airporter”, a proposal by Den Oudsten Bussen/Fokker Stork. However these proposals have been put forward in a manner that does not fully address one or more of the critical market entry or performance criteria resulting in a vehicle that has limited appeal or cannot meet the rigorous performance standards dictated by the transit agencies. In Europe, where road maintenance is superior relative to North America and durability is less of a concern, there has been little interest in lightweight composite vehicles, Den Oudsten Bussen created the RET X-98 which was to enter revenue service in Rotterdam, but aside from stirring momentary interest at a few shows, the modular vehicle could not save the company from bankruptcy. The Fokker-Stork body technology was licensed to APT Systems in Helmond NL which was incorporated into the Phileas, which has achieved little success. The license for the Fokker Stork body technology is held in North America by New Flyer but this again has achieved no commercial success.
One of the defining criteria is vehicle length. The market requires vehicles under 29 feet in length, 30 to 35 feet and 40 feet and 45 feet commuter buses together with 60 feet articulated vehicles. All previous attempts can be divided into two categories: one set of molds for each body length or various body lengths created by ganging modules. The multiple mold strategy of course provides a huge tooling expense. The multiple module technique has inherent weaknesses.
Up till now, therefore, no commercial vehicle of this type has been successfully exploited.
It will be appreciated that vehicles of this type can be used either as a light rail vehicle or as a road vehicle and many common features can be used in both structures. There are of course significant differences which will be well known to one skilled in the art but the principle set forth in the present application can in most cases be used in both fields.
A number of prior patents have been published showing features of the above mentioned commercial attempts and showing various other arrangements by other parties interested in this field.
The following patents have been noted as having some relevance in the present field
U.S. Pat. No. 5,042,395 (Wackerle) issued Aug. 27, 1991. Wackerle discloses a rail vehicle formed from molded upper section defining the side walls and roof connected to a floor section. The connection is provided by a corner piece which is bonded into an edge piece at each edge of each molded composite panel. The composite panels are formed from exterior sheets with a honey comb core between.
U.S. Pat. No. 5,140,913 (Takeichi) issued Aug. 25, 1992. Takeichi discloses a rail vehicle which is similarly constructed to the above except that it is formed in sections which are connected edge to edge along the length of the vehicle. The floor sections are formed from side beams and horizontal rails.
U.S. Pat. No. 6,433,151 (Ohara) issued Jul. 18, 1995 discloses a similar arrangement.
U.S. Pat. No. 5,904,972 (Tunis) issued May 18, 1999 discloses a technique for forming large composite core structures by vacuum assisted resin transfer molding. This is not particularly directed to vehicles but provides a technique which can form the large molded sections.
U.S. Pat. No. 5,918,548 (Elsner) issued Jul. 6, 1999 discloses a rail vehicle formed by connected beams.
U.S. Pat. No. 6,237,989 (Ammerlaan) issued May 29, 2001 discloses the arrangement of the Fokker Stork device described above which is defined as a molded structure formed by connected side panels, roof and floor sections where the drive components for the vehicle are bolted under the floor sections.
U.S. Pat. No. 6,686,254 (Emmons) issued Feb. 3, 2004 discloses a vehicle which is primarily formed from a roof section and a floor section together with vertical beams where the roof and floor sections are formed as a sandwich panel defined by the fibre reinforced sheets and an interconnecting core.
PCT Publication No. WO/2004/000633 and 000634 assigned to NABI published 31 Dec. 2003 discloses a molded structure in which the body and floor are separately molded from fibre reinforced plastics material and in particular the floor panel is formed of a tray shaped platform where the whole of the lower part of the vehicle is molded in one piece including the floor, part of the side wall and all of the structural connections for attachment to the components of the vehicle.